crowther



H. M. CROWTHER SPARK PLUG.

APPLICATlON FILED 001216.1919.

1,363,842; Patented Dec. 28,1921

1 F; e. I, Z

I N V EN TOR. HENRY/M. Cfiawmm ATTORNEYS.

E AET HENRY M. CROWTI-IER, O35 KINGIEAN, ARIZONA.

SPARK-PLUG.

Specification of Letters Patent.

Patented Dec.'28, 1929.

Application filed Gctober 16, 1919. Serial No. 331,164.

T 0 all whom it may concern Be it known that I, HENRY M. Cnowrrrnn, a citizen of the United States, residing at Kingman, in the county of Mohave and State of Arizona, have invented new and useful Improvements in Spark-Plugs, of

which the following is a specification.

My invention relate to spark plugs and consists of the novel features herein shown, described and claimed.

Figure l is a view in elevation of a spark plug embodying the principles of my invention.

Fig. 2 is a diametrical longitudinal sectional detail as on the line 22 of Fig. 1.

Fig. 3 is a bottom plan view as indicated by the arrow 3 in Fig. 1.

Fig. 4 is a fragmentary sectional detail of the outer end of a plug showing partly in section the fastener with one form of .conductor terminal attached thereto.

The metal case 1 has a hexagonal upper end 2 forming a wrench seat, a straight annular flange 3 extending upwardly from the wrench seat 2, the flange 3 being in line with the inner face 4 of the casing and there being a flat shoulder 5 at the upper end of the wrench seat outside of the flange 3, an externally screw-threaded nipple 6 extending downwardly from the wrench seat 2, and an annular flange 7 extending inwardly from the lower end of the nipple 6 thus forming a straight chamber 8 surrounded by the face 4 and an opening 9 through the flange 7.

The main insulator 10 is formed of a multiplicity of circular mica disks and the disks are cut to fit very tight in the chamber 8 upon the flange 7, and the insulator 10 has a circular central opening 11.

An asbestos gasket or cushion ring 12 fits tightly within the chamber 8 against the in sulator 10. The heavy metal retaining ring 13 is pressed tightly into the chamber 8 against the gasket 12 so as to hold the insulator 10 gas tight and so as to withstand the pressure of the explosion.

The threaded wire 14 is inserted through a binding nut 15, then through an asbestos washer 16, then through the opening 11 in the insulator 10, then through an asbestos washer 17, through a binding nut 18, through the terminal 19, through a spring washer 29 and through a binding nut 21. The upper end of the wire 14'is flattened and perforated to form an eye 22. A hook 23 is formed upon the lower end of the retractile coil spring 24, and the stem 25 extends irom the upper end of the spring 24.

A cushion ring 26 is made of asbestos paper saturated with shellac and tits tightly upon the flange 3. The auxiliary insulator 27 has a straight portion 28 fitting the cushion 2-6 and fitting the shoulder 5, a conical portion 29 extending upwardly from the straight portion 28, and the head 30 at the upper end of the conical portion 29. The insulator 2'? forms a conical chamber 31 extending upwardly from the chamber 8 there being a central opening 32 extending upwardly from the chamber 31 through the head 30. The stem 25 fits slidingly in the opening 32. The auxiliary insulator 2? simply serves as a cover for the case 1 and a mounting for the feed wire binding post.

A. metal cap 33 fits upon the head 30 and the edge 34 of the cap is spun into a groove around the head. 'A funnel-shaped socket 35 extends upwardly from the center of the cap 33 and has saw teeth 36 in its upper edge. The terminal or binding post 37 consists or" a conical plug 38 fitting in the socket 35 and a spherical head 39 extending upwardly from the plug, there being a neck 40 between the head and the ping and there being a central bore 41 to receive the stem 25 and a socket 42 at the upper end or" the bore 41. The stem 25 extends through the bore 41 and in making the spark plug the stem 25 is made over length and the stem 25'is pulled upwardly to give the spring 24 the desired ten sion, and then a spot is flattened in the stem 25 to form the head '43 and the wire is cut away above the head 43 and the head 43 released to settle into the socket 42. The socket 35 and the terminal 37 form a universal connector that will take a great variety of wire fasteners and hold the fasteners securely without the use of any nuts.

The coil spring 24 is of a comparatively light tension and the function of the coil spring is to assist in retaining the auxiliary insulator 27 in place and to allow for excessive expansion and contraction under heat and operation and to provide a spring terminal connection for the feed wire without the use of nuts. The wire 14, the head 22, the hook 23, the coil 24 and the stem 25 form the feed wire conductor to the spark gap terminal 19 and the case 1 forms the return conductor in the usual way.

The spark gap terminal 19 is circular in plan and is made of thin metal preferably coppe"-nicl-:el or copper-tungsten that it will he IQflLlCiOF-f to tea reudllv heat and cool under the I k for ignition Within the cylinder establishes itself betwe may es ablish itself at any edge or the l beck by [l uoint on its c tunce IlOlTl the e1 trouble uit heretofore made has been ing' cores will become coo.- luinp lcluclz, or our poor tion of the 1 s nii ure and this couti c; electric con- 0 carry the eecllCl U- from the central tee rod alon tl e t the insulutino core spurl: plugs the czrsil i return 51013 01'' the snarl: gap. in oreer tl n spark plug shall work sutisfac that the eitire force 01 t puss through the son 11: n) or v d e of the current due to the smol'e degosit upon the insulating core Will "eeuoe tie power and certiint v ot the spec It is not 11OSS211': lilfl b full short circ it he estrolishetl between the feed rod and the cesln to ruin the eiiieiencj of the spark plug. Anv continuous layer o: soot or snolie or carbon, .l of w ich n w; be called lzrnip black, or:-

tending; from the feed 1O along; the er'posed face of the insulating core to the cusin;,; reduces the ei'liciency ot' the s l-I to the e21- or" the current which wil f1: through layer of lamp block, and eil'ective or br-ul: in this layer of lamp bleo stog the leak, although the other ports may be 1 led with lamp black.

The lower face 55 of the main insulator 10 within the area of the ope ing 9 is e PPSGCl to the lump blncl: deposit a. d the object of the particular construction of the snark ga terminal 19 is to bring the portion 5:2 close enough to th s exposed face to burr the lump blscl: from the insulator and break the c'rcuit of electricity through the lump black from the nut 18 or the terminal 19 to the case 1.

The chamber 56 between the insulator 10 and the terminal 19 is substantially of even The meterial of the terninal 19 fl sh of the evplozling th sides and this terminal iiility so that it r i e, eiiee for on let '1. th rial 1s l hi gh conductivnt on n-n'l radiation that it will A c Kent? 0 t lesired extent to lower the re tune of the er;- 2) 1 l will he ahncst or q etuin l til.

then co e1 ter :1 u (l e the J11 J. tide, and LllG heart a ound the ternliiu explosion the terbe l ough to burn the u in th e 5T 0; tie insule v break I the continuity of tl ietu'een L119, terminz: l9 and tl. this time l'AQ lump 1 l; is l -actor noirlieat-c (11cm i sulutor and :i i 'h conducivity, h radio and deposit upon the inner L WM 4' J- 010 11 M1 oinei sui wees oi tie Ulllfllnul 1.1 rlilflg MEL 1 the period oi poor combustion will ignite and burn when the combustion improves sue the burning of this lets; black will asin heating; the terminal 19 and assist in burning the lump blue]: from the insulation face The layer of hung black 21S deposited is porous and more or less saturated Witl gen, and while it will not ignite b 'lll'QilCl is he CRSlllg ring is -1ile the mice ii sulntor is the preferred Iornfor my plug it is readily understood oisl: of other suitable rinterial such orcelain might be used.

oba 'ious that various changes might be made in the invention as herein set forth in its preferred form without departing from the spirit thereof as claimed.

I claim:

1. A spark plug comprising a casing having an inner screw threaded end carrying an inwardly extending flange, an outer insulator mounted upon the outer end of the casing, an inner insulator fixed within the inner end of the casing against the flange, a spark disk positioned upon the inner insulator and properly spaced therefrom and spaced to form a proper spark gap between it and the inner end of the casing, and a conductor rod comprising a means for oonnecting with the spark disk and passing through the inner insulator, a retractile spring within the casing and spaced from its inner wall and an outer extension passing through the outer insulator adapted to draw inwardly on the outer insulator.

2. A spark plug comprising a casing having an inner screw threaded end carrying an inwardly extending flange, an outer insulator mounted upon the outer end of the casing, an inner insulator fixed within the inner end of easing against the flange, means mounted on the inner insulator for forming a spark gap with the inner end of thecasing and a conductor rod comprising a means for connecting with the spark disk and passing through the inner insulator, a retractile spring within the casing and spaced from its inner wall and an outer extension passing through the outer insulator adapted to draw inwardly on the outer insulator.

3. A spark plug comprising a casinghaving an inner screw threaded end carrying an inwardly extending flange and an outer face and an extending annular member, an outer cone shaped insulator adapted to fit over the annular member and seat upon the outer face, a metallic cap having a funnel shaped outwardly extending portion fixed to the outer end of the insulator, an insulator comprising plurality of mica disks fitting closely the bore of the casing against the inwardly extending flange, a non-conducting gasket laid against the mica insulator, a metallic retaining ring pressed against the gasket whereby the insulator is retained in its position against the internal pressure developed in an engine cylinder, a threaded rod passing through a central bore in the mica insulator having set nuts on either side thereof, a spark disk mounted on the inwardly extending end of the rod and properly spaced from and parallel with the face of the mica insulator and spaced from the inner end'of the casing to form a proper spark gap, a retractile spring connecting with the end of the rod within the casing and extending outwardly through the end of the cone shaped insulator and terminating in a metallic fitting adapted to the funnel shaped cap and loosely connected therewith whereby a conductor connecting with the fitting may set up a circuit through the spring, through the spark disk across the gap returning through the casing.

4. A spark plug including a casing having an inner screw threaded end, an outer insulator mounted upon the outer end of said casing, an inner insulator fixed in the inner end of the casing, a spark disk mount ed upon the inner insulator and properly spaced therefrom and from the inner end of the casing, a terminal on the outer end of said'outer insulator, a conductor extending through said inner insulator and connected to said spark disk, a spring connected at one end to the inner end of said conductor and extending through said casing and said outer insulator and connected to said terminal and holding said disk, outer insulator and terminal in position.

5. A spark plug including a casing having an inner screw threaded end, an "outer insulator mounted upon the outer end of said casing, an inner insulator fixed in the inner end of the casing, a spark disk spaced from said inner insulator and from the inner end of said casing and forming a spark gap between it and the casing, a screw extending through said inner insulator and through said disk, a nut screwing on the outer end of said screw outside of said disk, a terminal on the outer end of said outer insulator, and a spring connected at one end to the inner end of said screw and extending through said casing, said outer insulator and connected at its other end to said terminal and holding said disk, said outer insulator and said terminal in position.

In testimony whereof I have signed my name to this specification.

HENRY M. onowrnnn. 

